For a resistive random access memory (RRAM) or phase change random access memory (PCRAM), a 1T1R array structure (1transistor and 1 resistive or phase change memory) is a commonly used array architecture. Compared with the 1T1R array structure, a 2D1R (2 diodes and 1 resistive or phase change memory) array structure may have higher operating current, lower leakage current, and higher array density.
In a conventional 2D1R array structure, a first diode of the two diodes includes a P+ doped region and an N-well, i.e., a PN junction is formed at the interface of the P+ doped region and the N-well, a second diode of the two diodes includes an N+ doped region and a P-well, i.e., a PN region is formed at the interface of the N+doped region and the P-well. In such a 2D1R array structure, the N-well of the first diode serves as a bit line, and the P-well of the second diode serves as a reset line.
However, the current inventors discovered that the above-described 2D1R array structure has a relatively low set current and reset current.